Thank you for contacting BibleAsk.
Although the book of Revelation contains symbolism, the numbers in it are not symbolic. For example, the 12 gates, the 12 foundations, and 12 different kinds of fruit on the tree of life they are literal. Also, all the dimensions of the New Jerusalem are built on the idea that these numbers have literal value. The numbers would be useless for adding if they were only symbolic. So, we can be sure that the numbers are literal numbers and not symbolic.
Though the 144,000 might be a literal number, the Scripture does not teach they are the only ones saved in the last days. John the Revelator tells us, in Revelation 7:9, after giving the list of the 12 tribes and the 144,000, about “a great multitude which no one could number, of all nations, tribes, peoples, and tongues, standing before the throne and before the Lamb, clothed with white robes, with palm branches in their hands.”
And in verse 13, one of the 24 elders asks John, “Who are these arrayed in white robes, and where did they come from?” Then, the elder answers his own question: “These are they which came out of great tribulation, and have washed their robes, and made them white in the blood of the Lamb” (v. 14).
The Scripture tells us of two great tribulations in prophecy. One which took place during the Papal persecution of the Dark Ages when millions of Christians were martyred for their faith. And the other one is called the “great tribulation” which points to the time before Christ’s second coming and is spoken of by Daniel the prophet: “And there shall be a time of trouble, Such as never was since there was a nation, Even to that time. And at that time your people shall be delivered, Every one who is found written in the book. And many of those who sleep in the dust of the earth shall awake, Some to everlasting life, Some to shame and everlasting contempt” (Daniel 12:1, 2).
Obviously, this great multitude who come out of great tribulation are saved by the ministry of the 144,000. Right after Pentecost, the 12 apostles preached to many, then after that there was a persecution (Acts 8:1). Likewise, after the Holy Spirit will be poured on the 144,000, a great multitude will be also saved and this will be followed by the great tribulation.
In His service,